In today's service provider networks, network edge devices, such as provider edge (PE) nodes, are configured to offer virtual private network (VPN) services to one or more customers. For instance, a PE node can simultaneously offer VPN services at layer 3 (L3), such as Internet Protocol (IP) VPN and at layer 2 (L2), such as Virtual Private Wire Service (VPWS) and Virtual Private Local Area Network (LAN) Service (VPLS), to satisfy customer requirements. As the number of VPN sites continue to grow, service providers are constantly expanding their networks to accommodate the growing demand for network resources. To expand the networks, service providers have historically installed new data cards to existing PE nodes until the PE nodes utilize all of their expansion capacity. When the PE nodes no longer have the capacity to accommodate new data cards, new PE nodes may be installed within the service provider networks to compensate for additional resource requirements. However, adding and fully configuring new network devices (e.g. new PE nodes) to the network often involves substantial costs both in the form of capital expenditures (CAPEX) and operational expenditures (OPEX).
In an attempt to reduce CAPEX and OPEX, Network Function Virtualization (NFV), as described in the European Telecommunications Standards Institute (ETSI) group specification (GS) NFV 002 v1.1.1, entitled “Network Functions Virtualisation (NFV); Architectural Framework,” published October 2013, which is incorporated herein as if reproduced in its entirety, consolidates many types of physical network devices onto one or more general purpose servers, switches, storage, and/or other general purpose network nodes. For example, NFV may implement network functions performed by a variety of physical network devices that include, but are not limited to switching elements (e.g. message routers and broadband network gateway), mobile network nodes (e.g. serving general packet radio service (GPRS) support node (SGSN)), traffic analysis (e.g. deep packet inspection (DPI) and quality of service (QoS) measurement), application level optimization (e.g. application accelerators and content distribution networks (CDNs)), and security functions (e.g. firewall). By consolidating the physical network devices, NFV provides greater flexibility for a network by implementing network functions that can be moved to and/or instantiated in various locations in the network without the installation and configuration of new physical network devices.
Unfortunately, current implementations of NFV address CAPEX reduction associated with network expansion, but do not fully address lowering the OPEX cost. One NFV virtualization technique, the appliance NFV method, treats a physical network device (e.g. PE node or Broadband Remote Access Server (BRAS)) as a single virtual appliance and embeds the entire physical network device into a virtual machine (VM) on a commodity server. For example, if the physical network device is a PE node, the appliance NFV method may implement the entire PE functionality as a single unit and embed all of the PE functionality within a single VM. Additionally, the PE data path can either be implemented on the same VM, or the PE data path can utilize the data path capabilities of commodity switches. As such, the appliance NFV method as described above primarily targets the CAPEX cost associated with expanding an existing PE node and/or adding a new PE node to the network. The appliance NFV method provides relatively low OPEX cost reduction because the newly added PE nodes may still need to be fully configured and installed within a service provider network.